1. Field of the Invention
The present invention relates to a neutralization testing apparatus and a neutralization testing method of a liquid sample such as lubricant oil and may be utilized in measuring an acid neutralization rate of cylinder oil which is heavy lubricant oil for example.
2. Description of Related Art
Hitherto, lubrication by means of fats and oils has been used frequently in a driving mechanism such as an engine. For instance, cylinder oil for smoothly driving a piston within an engine cylinder is used in a ship engine, beside system oil used for smoothly actuating the driving mechanism.
In addition to the performance of smoothly driving the piston within a high temperature and high pressure atmosphere within the cylinder, such cylinder oil is required to have a performance of neutralizing corrosive sulfur compound which is produced within the cylinder along the combustion of fuel oil to prevent the cylinder and piston from corroding.
Accordingly, it is an important factor to find an acid neutralization rate as the performance of the cylinder oil in developing the cylinder oil. Therefore, the performance of the cylinder oil has been evaluated by finding the neutralization reaction rate of the cylinder oil by using an acid neutralization testing apparatus since the past.
As the acid neutralization testing apparatus of the cylinder oil, a testing apparatus for finding a neutralization reaction time of sulfuric acid and the cylinder oil and for finding the acid neutralization rate from that by charging the cylinder oil which is a liquid sample into a closed container whose internal temperature and pressure are kept constant, by injecting the sulfuric acid to the closed container by an injector via a reagent injecting port which is in communication with the inside of the closed container and by measuring changes in pressure within the closed container.
In such an acid neutralization testing apparatus, there has been provided an air-tight valve at the reagent injecting port and the sulfuric acid has been injected through a series of works of (1) opening the valve, (2) inserting the injector needle to inject the sulfuric acid, and (3) closing the valve.
Then, the time when the valve is closed has been set as a neutralization reaction starting time of the cylinder oil and the acid neutralization rate of the cylinder oil has been found from the elapsed change in the increase of pressure within the testing apparatus after that.
However, there has been a problem that the neutralization reaction rate cannot be found accurately when the measurement is carried out by means of the above-mentioned acid neutralization testing apparatus in a high temperature range in which the reaction takes place quickly because gas leaks as the valve is opened and the measuring conditions within the closed container change.
Further, it has been difficult to set the measuring conditions of the high temperature and high pressure atmosphere like that in an actual cylinder by the prior art acid neutralization testing apparatus.
Due to that, there has been a problem that the cylinder oil cannot be measured directly because the cylinder oil which is highly viscous in a normal temperature has to be diluted in measuring it.
Further, when the time when the valve is closed is set as the neutralization reaction starting time as described above, a time lag is produced between that time and the actual neutralization starting time when the sulfuric acid contacts with the cylinder oil. Therefore, there has been a problem that the neutralization reaction time until when the reaction ends cannot be found accurately and the neutralization reaction rate cannot be found accurately.
Accordingly, the present invention has been devised in order to solve the aforementioned problems by providing a neutralization testing apparatus and a neutralization testing method which allow the neutralization reaction rate of a liquid sample such as lubricant oil to be measured accurately.